lib/libc/inet/inet_cidr_pton.c

   1 /*      $NetBSD: inet_cidr_pton.c,v 1.6 2009/04/12 17:07:16 christos Exp $      */
   2
   3 /*
   4  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   5  * Copyright (c) 1998,1999 by Internet Software Consortium.
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  17  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19
  20 #include <sys/cdefs.h>
  21 #if defined(LIBC_SCCS) && !defined(lint)
  22 #if 0
  23 static const char rcsid[] = "Id: inet_cidr_pton.c,v 1.6 2005/04/27 04:56:19 sra Exp";
  24 #else
  25 __RCSID("$NetBSD: inet_cidr_pton.c,v 1.6 2009/04/12 17:07:16 christos Exp $");
  26 #endif
  27 #endif
  28
  29 #include "port_before.h"
  30
  31 #include "namespace.h"
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34 #include <netinet/in.h>
  35 #include <arpa/nameser.h>
  36 #include <arpa/inet.h>
  37
  38 #include <isc/assertions.h>
  39 #include <ctype.h>
  40 #include <errno.h>
  41 #include <stdio.h>
  42 #include <string.h>
  43 #include <stdlib.h>
  44
  45 #include "port_after.h"
  46
  47 #ifdef SPRINTF_CHAR
  48 # define SPRINTF(x) strlen(sprintf/**/x)
  49 #else
  50 # define SPRINTF(x) ((size_t)sprintf x)
  51 #endif
  52
  53 #ifdef __weak_alias
  54 __weak_alias(inet_cidr_pton,_inet_cidr_pton)
  55 #endif
  56
  57 static int      inet_cidr_pton_ipv4 __P((const char *src, u_char *dst,
  58                                          int *bits, int ipv6));
  59 static int      inet_cidr_pton_ipv6 __P((const char *src, u_char *dst,
  60                                          int *bits));
  61
  62 static int      getbits(const char *, int ipv6);
  63
  64 /*%
  65  * int
  66  * inet_cidr_pton(af, src, dst, *bits)
  67  *      convert network address from presentation to network format.
  68  *      accepts inet_pton()'s input for this "af" plus trailing "/CIDR".
  69  *      "dst" is assumed large enough for its "af".  "bits" is set to the
  70  *      /CIDR prefix length, which can have defaults (like /32 for IPv4).
  71  * return:
  72  *      -1 if an error occurred (inspect errno; ENOENT means bad format).
  73  *      0 if successful conversion occurred.
  74  * note:
  75  *      192.5.5.1/28 has a nonzero host part, which means it isn't a network
  76  *      as called for by inet_net_pton() but it can be a host address with
  77  *      an included netmask.
  78  * author:
  79  *      Paul Vixie (ISC), October 1998
  80  */
  81 int
  82 inet_cidr_pton(int af, const char *src, void *dst, int *bits) {
  83         switch (af) {
  84         case AF_INET:
  85                 return (inet_cidr_pton_ipv4(src, dst, bits, 0));
  86         case AF_INET6:
  87                 return (inet_cidr_pton_ipv6(src, dst, bits));
  88         default:
  89                 errno = EAFNOSUPPORT;
  90                 return (-1);
  91         }
  92 }
  93
  94 static const char digits[] = "0123456789";
  95
  96 static int
  97 inet_cidr_pton_ipv4(const char *src, u_char *dst, int *pbits, int ipv6) {
  98         const u_char *odst = dst;
  99         int n, ch, tmp, bits;
 100         size_t size = 4;
 101
 102         /* Get the mantissa. */
 103         while (ch = *src++, (isascii(ch) && isdigit(ch))) {
 104                 tmp = 0;
 105                 do {
 106                         n = strchr(digits, ch) - digits;
 107                         INSIST(n >= 0 && n <= 9);
 108                         tmp *= 10;
 109                         tmp += n;
 110                         if (tmp > 255)
 111                                 goto enoent;
 112                 } while ((ch = *src++) != '\0' && isascii(ch) && isdigit(ch));
 113                 if (size-- == 0U)
 114                         goto emsgsize;
 115                 *dst++ = (u_char) tmp;
 116                 if (ch == '\0' || ch == '/')
 117                         break;
 118                 if (ch != '.')
 119                         goto enoent;
 120         }
 121
 122         /* Get the prefix length if any. */
 123         bits = -1;
 124         if (ch == '/' && dst > odst) {
 125                 bits = getbits(src, ipv6);
 126                 if (bits == -2)
 127                         goto enoent;
 128         } else if (ch != '\0')
 129                 goto enoent;
 130
 131         /* Prefix length can default to /32 only if all four octets spec'd. */
 132         if (bits == -1) {
 133                 if (dst - odst == 4)
 134                         bits = ipv6 ? 128 : 32;
 135                 else
 136                         goto enoent;
 137         }
 138
 139         /* If nothing was written to the destination, we found no address. */
 140         if (dst == odst)
 141                 goto enoent;
 142
 143         /* If prefix length overspecifies mantissa, life is bad. */
 144         if (((bits - (ipv6 ? 96 : 0)) / 8) > (dst - odst))
 145                 goto enoent;
 146
 147         /* Extend address to four octets. */
 148         while (size-- > 0U)
 149                 *dst++ = 0;
 150
 151         *pbits = bits;
 152         return (0);
 153
 154  enoent:
 155         errno = ENOENT;
 156         return (-1);
 157
 158  emsgsize:
 159         errno = EMSGSIZE;
 160         return (-1);
 161 }
 162
 163 static int
 164 inet_cidr_pton_ipv6(const char *src, u_char *dst, int *pbits) {
 165         static const char xdigits_l[] = "0123456789abcdef",
 166                           xdigits_u[] = "0123456789ABCDEF";
 167         u_char tmp[NS_IN6ADDRSZ], *tp, *endp, *colonp;
 168         const char *xdigits, *curtok;
 169         int ch, saw_xdigit;
 170         u_int val;
 171         int bits;
 172
 173         memset((tp = tmp), '\0', NS_IN6ADDRSZ);
 174         endp = tp + NS_IN6ADDRSZ;
 175         colonp = NULL;
 176         /* Leading :: requires some special handling. */
 177         if (*src == ':')
 178                 if (*++src != ':')
 179                         return (0);
 180         curtok = src;
 181         saw_xdigit = 0;
 182         val = 0;
 183         bits = -1;
 184         while ((ch = *src++) != '\0') {
 185                 const char *pch;
 186
 187                 if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
 188                         pch = strchr((xdigits = xdigits_u), ch);
 189                 if (pch != NULL) {
 190                         val <<= 4;
 191                         val |= (pch - xdigits);
 192                         if (val > 0xffff)
 193                                 return (0);
 194                         saw_xdigit = 1;
 195                         continue;
 196                 }
 197                 if (ch == ':') {
 198                         curtok = src;
 199                         if (!saw_xdigit) {
 200                                 if (colonp)
 201                                         return (0);
 202                                 colonp = tp;
 203                                 continue;
 204                         } else if (*src == '\0') {
 205                                 return (0);
 206                         }
 207                         if (tp + NS_INT16SZ > endp)
 208                                 return (0);
 209                         *tp++ = (u_char) (val >> 8) & 0xff;
 210                         *tp++ = (u_char) val & 0xff;
 211                         saw_xdigit = 0;
 212                         val = 0;
 213                         continue;
 214                 }
 215                 if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
 216                     inet_cidr_pton_ipv4(curtok, tp, &bits, 1) == 0) {
 217                         tp += NS_INADDRSZ;
 218                         saw_xdigit = 0;
 219                         break;  /*%< '\\0' was seen by inet_pton4(). */
 220                 }
 221                 if (ch == '/') {
 222                         bits = getbits(src, 1);
 223                         if (bits == -2)
 224                                 goto enoent;
 225                         break;
 226                 }
 227                 goto enoent;
 228         }
 229         if (saw_xdigit) {
 230                 if (tp + NS_INT16SZ > endp)
 231                         goto emsgsize;
 232                 *tp++ = (u_char) (val >> 8) & 0xff;
 233                 *tp++ = (u_char) val & 0xff;
 234         }
 235         if (colonp != NULL) {
 236                 /*
 237                  * Since some memmove()'s erroneously fail to handle
 238                  * overlapping regions, we'll do the shift by hand.
 239                  */
 240                 const int n = tp - colonp;
 241                 int i;
 242
 243                 if (tp == endp)
 244                         goto enoent;
 245                 for (i = 1; i <= n; i++) {
 246                         endp[- i] = colonp[n - i];
 247                         colonp[n - i] = 0;
 248                 }
 249                 tp = endp;
 250         }
 251
 252         memcpy(dst, tmp, NS_IN6ADDRSZ);
 253
 254         *pbits = bits;
 255         return (0);
 256
 257  enoent:
 258         errno = ENOENT;
 259         return (-1);
 260
 261  emsgsize:
 262         errno = EMSGSIZE;
 263         return (-1);
 264 }
 265
 266 static int
 267 getbits(const char *src, int ipv6) {
 268         int bits = 0;
 269         char *cp, ch;
 270
 271         if (*src == '\0')                       /*%< syntax */
 272                 return (-2);
 273         do {
 274                 ch = *src++;
 275                 cp = strchr(digits, ch);
 276                 if (cp == NULL)                 /*%< syntax */
 277                         return (-2);
 278                 bits *= 10;
 279                 bits += cp - digits;
 280                 if (bits == 0 && *src != '\0')  /*%< no leading zeros */
 281                         return (-2);
 282                 if (bits > (ipv6 ? 128 : 32))   /*%< range error */
 283                         return (-2);
 284         } while (*src != '\0');
 285
 286         return (bits);
 287 }
 288
 289 /*! \file */